|Mission type||Asteroid sample return|
|Mission duration||10 years (planned)|
|Launch mass||≤2,000 kg (4,400 lb)|
|Start of mission|
|Rocket||Long March 3B|
|469219 Kamoʻoalewa orbiter|
|Sample mass||≥100 g (0.2 lb)|
ZhengHe , also known as Tianwen-2, is a planned Chinese asteroid sample-return and comet exploration mission that is currently under development.
Named after the 15th century explorer of the Ming Dynasty, ZhengHe is planned to be launched by a Long March 3B rocket around 2025. It will use solar electric propulsion to explore the co-orbital near-Earth asteroid 469219 Kamoʻoalewa and the main-belt comet 311P/PANSTARRS. The spacecraft will rendezvous with Kamoʻoalewa and conduct remote sensing observations in orbit, before landing on the asteroid to collect a sample of 200–1,000 g (7.1–35.3 oz) of regolith. A nano-orbiter and nano-lander will be deployed to conduct remote sensing and sampling observations, and explosives will be used to expose potential subsurface volatiles for detection.
The spacecraft will use both anchor-and-attach and touch-and-go methods to attempt collection of a sample from the asteroid. It would be the first time an anchor-and-attach method has been used on an asteroid, as both OSIRIS-REx and Hayabusa2 used touch-and-go.
ZhengHe will then return to Earth to drop off a return capsule containing the sample and conduct a gravity assist maneuver to propel the spacecraft toward Mars, where a second gravity assist will be performed to direct it to 311P/PANSTARRS. A flyby of an unnamed asteroid may also be attempted en route to 311P/PANSTARRS. Remote sensing and in-situ measurements will be conducted at 311P/PANSTARRS for at least one year.
In 2018, a deep space exploration roadmap covering the 2020–2030 timeframe was proposed by researchers at the Chinese Academy of Sciences, which included an asteroid exploration mission planned for launch around 2022 or 2024. In spring 2019, after a design study for the mission was carried out by the Chinese Academy of Space Technology (CAST), the CNSA began soliciting international proposals for scientific instruments to be carried on ZhengHe.
ZhengHe will incorporate several types of instruments, including wide/narrow angle multispectral and color cameras, a thermal emission spectrometer, a visible/near-infrared imaging spectrometer, a mass spectrometer, a magnetometer, and a charged/neutral particle and dust analyzer. International contributions to these payloads are being encouraged.
The United Kingdom is considering a proposal for a penetrator to deliver a mass spectrometer to probe the subsurface ice of 311P/PANSTARRS.